Previously, in a field of a drive apparatus (an actuator), which includes a motor unit, there is known a sealing technique, which limits intrusion of water into, for example, the motor unit or an inverter that supplies an electric power to the motor unit. For example, JP5260198B2 (corresponding to US2011/0091337A1) discloses an electric compressor, which has an inverter integrated therein. In this electric compressor, a liquid gasket (liquid sealant) is filled in a groove that is formed in a flange of an inverter receiving portion to fluid-tightly seal between the flange and a closure.
The liquid sealant of JP5260198B2 (corresponding to US2011/0091337A1) is filled into and is cured in the groove that is leveled, and thereby the liquid sealant can be applicable only to a connection between two planar surfaces, which are opposed to each other in a direction perpendicular to the planar surfaces. Furthermore, the filling process of the liquid sealant causes an increased number of manufacturing steps. In contrast, a seal member, such as an O-ring and a packing, can be used in both of the connection between the planar surfaces, which are opposed to each other in the direction perpendicular to the planar surfaces, and a connection (a radial fitting) between two radially opposed surfaces, which are opposed to each other in a radial direction.
However, in a case where a drive apparatus, which includes three units, i.e., a motor case configured into a cup form, a closure for covering an opening of the motor case, and a control device cover for receiving a control device, is fixed to an installation subject, seals (sealing means) are required at three locations, respectively, which include two locations among the three units (i.e., a location between a first unit and a second unit and a location between a second unit and a third unit) and one location between the drive apparatus and the installation subject. Therefore, the locations, at each of which the waterproof quality needs to be guaranteed, are disadvantageously increased, and the number of steps for installing the seals (the sealing means) is disadvantageously increased.